SendGrid vs Mailgun
Two veterans of the transactional email space, both now part of larger telco-style parents.
What matters for teams building autonomous agents
An agent stack treats email as a two-way primitive. Inbound has to arrive as structured JSON a tool call can consume, sends have to be safe to retry when a model loop repeats itself, and every action needs an audit trail. A provider without inbound parsing only solves half the problem.
| Priority | SendGrid | Mailgun |
|---|---|---|
| Inbound parsing | Yes | Yes |
| Idempotency keys | No | No |
| Webhooks | Yes | Yes |
| Operating since | 2009 | 2010 |
| Event stream | Yes | Yes |
| Best published rate per 1,000 | $0.40 | $0.70 |
| Batch sending | Yes | Yes |
| SDKs | node, python, go, ruby, php, java, dotnet | node, python, go, ruby, php, java |
| Multi-tenant | Yes | Yes |
For an agent that reads and writes email running inbound parsing into tool calls and model-generated sends that must not duplicate, SendGrid takes every priority that separates them here (operating track record, best published rate per 1,000, and SDK breadth), while Mailgun matches it on the rest. That ordering reflects this audience. Weigh the same table differently and the answer changes.
Side by side
| Feature | SendGrid | Mailgun |
|---|---|---|
| Webhooks | Yes | Yes |
| SDKs | node, python, go, ruby, php, java, dotnet | node, python, go, ruby, php, java |
| Multi-tenant | Yes | Yes |
| Tagline | Twilio-owned veteran with broad SDK coverage. | Developer-leaning email infra, owned by Sinch. |
| Free tier | 60-day free trial only (permanent free tier was removed May 2025) | 100/day permanent free plan |
| Starts at | $19.95/mo for 50,000 emails | $15/mo for 10,000 emails (Basic) |
| Pricing model | tiered | tiered |
| API | Yes | Yes |
| SMTP | Yes | Yes |
| Templates | rich | rich |
| React Email | No | No |
| Inbound | Yes | Yes |
| Idempotency | No | No |
| Dedicated IP | Yes | Yes |
| Deliverability | Established delivery infrastructure, but shared-IP reputation can vary and the product is broader than pure transactional delivery. | Generally good, with deliverability monitoring tools available on higher tiers. Inbound routes and suppressions are battle-tested. |
| DX score | 6/10 | 7/10 |
| Best for | Enterprises that want a single Twilio-backed vendor for email and SMS. | Technical teams that want SMTP relay plus advanced routing. |
SendGrid
- ›Mature, broad SDK coverage
- ›Twilio backing means long-term operational stability
- ›Marketing platform alongside transactional
- ›Inbound parse webhook is well-documented
- ›Removed the permanent free tier in May 2025
- ›No idempotency keys
- ›No API request logs for debugging
- ›Pricing climbs steeply across plan tiers; many features gated to higher SKUs
- ›Legacy v3 API patterns feel dated next to Resend or MailerSend
Mailgun
- ›Strong SMTP relay support, useful when migrating off self-hosted Postfix
- ›Inbound routes with regex matching
- ›Validation and parsing tools available
- ›Sub-accounts for agency use cases
- ›Overage pricing and plan differences need close review at scale
- ›Documentation is comprehensive but occasionally out of date
- ›No idempotency keys
- ›Sinch ownership has moved focus toward enterprise